Suggestion
Give a human manager the option to "shadow" someone. That is, allow the option to take over the identity of an existing Commissioner, Owner, GM, or Field Manager. Explanation: Currently, if you want to take over a certain job, you will have your own identity (regardless of whether you use your own name or give yourself the name of a real-life baseball person.) So let's say you want to take over as manager of the Yankees. In OOTP '07, you can give yourself the name "Joe Torre", but your record/history begins and ends with you. In other words, you ARE Joe Torre. However, in Shadow Mode, you could select Joe Torre within the game and assume his identity. Thus, you pick up his record/history where it is and add to it while you are "playing" him. Later, you could exit Shadow Mode and the Computer Joe Torre takes over again with the record you accumulated while you were him. (Hope this isn't too terribly confusing

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Reason
While some of us may like the idea of seeing ourselves as Commissioner or a GM within our baseball universe, others may want to give their universe a more realistic, "undisturbed" feel.
Priority
LOW to LOW-MEDIUM. I hate to give any of my suggestions a low priority, but I realize this isn't absolutely imperative to my enjoyment of the game, so... meh
